Maybe we are talking about different things here.

Autonumbering is very different from AutoCorrect. If you make a typed number rather than an Automatic number part of your AutoCorrect entry you will have it as part of your autocorrect.

By the way, hard page breaks (Ctrl-Enter) are not good. Much better is formatting for the first paragraph that is "page break before." This is because Word treats a hard page break as being inside a paragraph. It can give you very strange results when you make formatting changes to the first paragraph on a page and those changes also are made to the last paragraph on the preceding page. (This may have been fixed in recent versions, I haven't checked.)